Aminoacyl-t-RNA-synthetases

Knorre, D. G., Lavrik, O. I. Affinity labeling of aminoacyl-t-RNA synthetases, in Theory and Practice in Affinity Techniques, (ed. Sundaram, P. V., Eckstdn, F.) Academic Press, Lonson 1978, p. 169... 

Synthesis using Aminoacyl t-RNA Synthetase. Other interesting synthetic reactions using ATP are the use of aminoacyl t-RNA synthetase (ARS, E.C. sub-class 6.1.1) to synthesize peptides (9-72) and for the construction of the fascinating biologically-active nucleotide, diadenosine polyphosphate (Ap4A) (13-14). ARS isolated from mesophiles is quite unstable and is usually handled on ice. ARS from B. stearothermophilus, on the other hand, is quite stable and is a useful catalyst for bioreactors. 

Catalytic residues present in motif 2 and motif 3 of Class II aminoacyl t-RNA synthetases (EC - E. coli SC - S. cerevisiae HA - Hamster TT - Thermus thermopilus)... 

The geometry of superimposed residues (Fig. 4) is substantially different from analogous model obtained for Class I t-RNA synthetases 40]. It indicates that the electrostatic field enhancing the rate of ATP aminoacylation... 

Figure 13-2. Enzymatic synthesis of p. p hdifadenosine 5 -)tetraphos-phate (Ap4A 1) with aminoacyl tRNA synthetases (ARS). AA can be leucine, for example, and ARS leucyl t-RNA synthetase1111.

Norris, A. T. and Berg, P. (1964) Mechanism of aminoacyl RNA synthesis studies with isolated aminoacyl adenylate complexes of isoleucyl RNA synthetase. Proc. Nat. Acad. Sci. 52, 330. 

When a wrong amino acid is placed on the transfer RNA, for example when Cys-tRNA is chemically reduced to Ala-tRNA > t. the synthetase (Cys) becomes unable to remove the wrong amino acid (Ala), finally resulting in the synthesis of a wrong protein. A correct insertion is thus entirely dependent upon the conformable sites involved in the mutual recognition of the transfer RNA, and the aminoacyl-RNA synthetase. 

Hendrickson T, Schimmel P. Transfer RNA-dependent amino acid discrimination by aminoacyl-tRNA synthetases. In Translation Mechanisms. Lapointe J, Brakier-Gingras L, eds. 2003. Kluwer Academic/Plenum Publishers, New York. p. 34-64. 

An RNA aptamer has been selected to activate the carboxylic acid of amino acids that mimics the formation of a mixed phosphate anhydride synthesis of aminoacyl tRNA synthetases. The optimal aptamer requires only Ca + for the reaction, and operates at low pH with Xm 50 mM and /ccat 1.1 min for the activation of leucine. This lends support to the concept of translation in an RNA-based world. An RNA-cleaving DNAzyme has been used to target a chemokine receptor required by HIV-1 for entry into susceptible cells. The DNAzyme was found to be very efficient, and specifically interfered with the fusion of cells that harboured the T-lymphocytotropic HIV-1 envelope. 

Uter, N.T., Gruic-Sovulj, L, Perona, J.J. Amino acid-dependent transfer RNA affinity in a class 1 aminoacyl-tRNA synthetase. J. Biol. Chem. 2005,280,23966-77. 

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